The field of the disclosure relates generally to service electric generation systems and propulsion systems, and more specifically to a ship propulsion system configured to also provide power to a ship service bus.
At least some known marine vessels include a ship-service generator set that includes an engine driving a generator. The generator set is utilized to provide power to an electric distribution system within the vessel. The electric distribution system includes a ship-service bus. A plurality of loads are coupled to the ship-service bus and receive power from the electric distribution system. Known marine vessels also include a propulsion system. Typically, the propulsion system includes a prime mover that drives a propulsion device, for example, a propeller. Some known propulsion systems are referred to as hybrid propulsion systems, and may include an electric motor to drive the propulsion device, or aid the prime mover in driving the propulsion device.
Known marine vessels may also include uninterruptible power supplies (UPS) connected to certain equipment within the vessel that is deemed to be critical to the vessels operation. Since the ship-service generator set, the propulsion system, and the UPS are separate systems, each system adds components to the contents of the marine vessel, requiring space and adding weight to the vessel. Moreover, it may be advantageous for the sake of redundancy, to couple more than one ship-service generator set to the electric distribution system to ensure electricity is available even in the event one generator set is not operating. Each ship-service generator set may be run at a fraction of rated load so that if one of the generator sets malfunctions, the other generator sets can supply the full electrical load without interruption of power. Since generator set engines, for example gas turbine engines, operate most efficiently at or near a rated power, this redundant configuration may limit the efficiency of the electrical distribution system. A vessel that includes a UPS, which may provide power to select components of the vessel until a backup generator set is started and brought online, may operate the main generator set at a higher load, and therefore higher efficiency.